The present invention relates generally to the control of exhaust and intake valves during positive power and engine braking. In particular, the present invention is directed to an assembly to modify the valve lift and timing of the exhaust valve and/or intake valve during positive power and different operating conditions during positive power.
It has been published that an exhaust event with an internal hot exhaust gas recirculation (xe2x80x9cEGRxe2x80x9d) event is beneficial in controlling emissions by directing a small amount of the exhaust gas back into the valve cylinder to mix with intake air. The combined intake and exhaust gas with the depleted oxygen helps create a lower burn temperature, which helps reduce the generation of nitrogen oxides. There are, however, certain positive power conditions during which the EGR event does not add any benefit. These conditions include a light load and low engine rpm. The EGR event also does not provide any benefit during engine braking where the EGR event reduces braking power. Therefore, it is desirable to have the EGR event to be selectable, on as desired during positive power and off during braking.
It is an object of the present invention to provide a device for an engine that can change the intake valve lift of an intake valve.
It is another object of the present invention to provide a device for an engine that can change the timing of the intake valve.
It is another object of the present invention to provide a device for an engine that can change the timing of the intake valve to improve emission and fuel economy.
It is another object of the present invention to provide a device for an engine that can advance or retard the timing of the intake valve to improve emission and fuel economy.
It is another object of the present invention to provide a device for an overhead cam diesel engine that can change the intake valve lift of the intake valve.
It is another object of the present invention to provide a device for an overhead cam diesel engine that can change the timing of the intake valve.
It is an object of the present invention to provide a device for an engine that can change the exhaust valve lift of an exhaust valve.
It is another object of the present invention to provide a device for an engine that can change the timing of the exhaust valve.
It is another object of the present invention to provide a device for an engine that can change the timing of the exhaust valve to improve emission and fuel economy.
It is another object of the present invention to provide a device for an engine that can advance or retard the timing of the exhaust valve to improve emission and fuel economy.
It is another object of the present invention to provide a device for an overhead cam diesel engine that can change the exhaust valve lift of the exhaust valve.
It is another object of the present invention to provide a device for an overhead cam diesel engine that can change the timing of the exhaust valve.
It is another object of the present invention to provide a device for an engine that permits the exhaust valve to operate with an EGR event when desired.
It is another object of the present invention to provide a device for an engine that permits an EGR event during selected operating conditions during positive power.
It is another object of the present invention to provide a device for an engine that does not permit an EGR event during engine braking.
The present invention is directed to an apparatus for operating at least one intake valve and at least one exhaust valve in an engine cylinder. The apparatus according to an embodiment of the present invention includes an exhaust valve operating assembly for operating the at least one exhaust valve of the engine cylinder, wherein the exhaust valve operating assembly is capable of producing an exhaust gas recirculation event. The apparatus further includes an intake valve operating assembly for operating the at least one intake valve of the engine cylinder, and exhaust modifying assembly for modifying the operation of the exhaust valve operating assembly during a predetermined engine operating condition.
In accordance with the present invention, the exhaust modifying assembly modifies the timing of the at least one exhaust valve during the predetermined engine operating condition. The predetermined engine operating condition is at least one of a first positive power operating condition, a second positive power operating condition and an engine braking condition.
In accordance with the present invention, the exhaust modifying assembly also modifies the lift of the at least one exhaust valve during the predetermined engine operating condition. The predetermined engine operating condition is at least one of a first positive power operating condition, a second positive power operating condition and an engine braking condition.
The exhaust valve operating assembly may include an exhaust rocker arm assembly pivotably mounted on a rocker shaft. The exhaust modifying assembly may include a hydraulic assembly in communication with the rocker shaft for controlling the operation of the at least one exhaust valve. The exhaust modifying assembly may further include a lash adjuster assembly on the exhaust rocker arm. The exhaust modifying assembly may further include a releasable assembly for releasably engaging a slot within the rocker shaft during the predetermined engine operating condition, wherein the releasable assembly controls the rotation of the exhaust rocker arm to modify at least one of the lift and timing of the at least one exhaust valve. The releasable assembly inhibits the operation of the lash adjuster assembly when the releasable assembly is located within the slot. Furthermore, the releasable assembly inhibits the exhaust gas recirculation event when the releasable assembly is received within the slot.
The apparatus according to another embodiment of thee present invention includes an exhaust valve operating assembly for operating the at least one exhaust valve of the engine cylinder, an intake valve operating assembly for operating the at least one intake valve of thee engine cylinder, and an intake modifying assembly for modifying the operation of the intake valve operating assembly during a predetermined engine operating condition.
In accordance with the present invention, the intake modifying assembly may modify the timing of the at least one intake valve during the predetermined engine operating condition. The predetermined engine operating condition is at least one of a first positive power operating condition, a second positive power operating condition and an engine braking condition.
In accordance with the present invention, the intake modifying assembly may further modify the lift of the at least one intake valve during the predetermined engine operating condition. The predetermined engine operating condition is at least one of a first positive power operating condition, a second positive power operating condition and an engine braking condition.
The intake valve operating assembly may include an intake rocker arm assembly pivotably mounted on a rocker shaft. The intake modifying assembly may include a hydraulic assembly in communication with the rocker shaft for controlling the operation of the at least one intake valve. The intake modifying assembly may further include a lash adjuster assembly on the intake rocker arm. The intake modifying assembly further includes a releasable assembly for releasably engaging a slot within the rocker shaft during the predetermined engine operating condition, wherein the releasable assembly controls the rotation of the intake rocker arm to modify at least one of the lift and timing of the at least one intake valve. The releasable assembly inhibits the operation of the lash adjuster assembly when the releasable assembly is located within the slot.
The present invention also is directed to an apparatus for operating at least one intake valve and at least one exhaust valve in an engine cylinder. The apparatus may include an exhaust valve operating assembly for operating the at least one exhaust valve of the engine cylinder, wherein the exhaust valve operating assembly is capable of producing an exhaust gas recirculation event. The apparatus also includes an intake valve operating assembly for operating the at least one intake valve of the engine cylinder. The apparatus may further include an exhaust modifying assembly for modifying the operation of the exhaust valve operating assembly during a predetermined engine operating condition and an intake modifying assembly for modifying the operation of the intake valve operating assembly during a predetermined engine operating condition.
The exhaust modifying assembly may modify the timing and lift of the at least one exhaust valve during the predetermined engine operating condition. The predetermined engine operating condition is at least one of a first positive power operating condition, a second positive power operating condition and an engine braking condition.
The intake modifying assembly may modify the timing and lift of the at least one intake valve during the predetermined engine operating condition. The predetermined engine operating condition is at least one of a first positive power operating condition, a second positive power operating condition and an engine braking condition.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated herein by reference, and which constitute a part of this specification, illustrate certain embodiments of the invention and, together with the detailed description, serve to explain the principles of the present invention.